Reverse-osmosis tubular membrane modules typically comprise a plurality of tubular membranes positioned within a tubular outer pressure tube, wherein each end of the outer pressure tube and the inner membrane tube is secured to a pair of tube plate sheets, to form a reverse-osmosis membrane module, such as, for example, of the type shown and disclosed in U.S. Pat. No. 4,309,287, issued Jan. 5, 1982. In such a reverse-osmosis membrane module, each tube sheet is characterized by one or usually more, such as from three to five, straight, tubular, permeate-collection passageways which extend generally perpendicular to the axis of the membrane tube. Individual tubular permeate passageways extend from the end of each of the individual membrane tubes into a permeate-collection passageway, and typically in a staggered, spaced-apart manner, so that permeate flow occurs from the exterior surface of the membrane tube within the outer pressure tube into one or both ends of the tube and into the individual permeate flow passageways. The flow of all of the individual flow passageways is spaced apart and based on either side of the permeate-collection flow passageways and is collected and withdrawn from the membrane module. Often, it is desirable to stack the individual membrane modules, so that the permeate collected in one module flows directly into the permeate-collection flow passageway of the next module, until it is subsequently withdrawn. There are other arrangements by which multiple-tube reverse-osmosis modules, having straight permeate-collection flow passageways, are arranged and employed, and the membrane module, as disclosed in U.S. Pat. No. 4,309,287, issued Jan. 5, 1982, is merely illustrative of reverse-osmosis membrane modules.
During operation of the reverse-osmosis, multiple-tube module, it is desirable; for example, with water-desalination modules, to collect and to test the quality of the permeate produced from individual tubes of a module or a group of modules, in order to determine if the permeate is the desired quality of whether there is a leaking membrane or leaking seal in the module. The quality of the permeate from individual modules can be monitored, by taking a test sample during operation and then subjecting the test sample to suitable analytical means, such as conductivity tests, to determine the amount of low-molecular-weight salt in the test permeate collected. However, where the test permeate from a module indicates an unacceptable permeate from the module, it has been the practice to remove and to replace the entire module; for example, of from a five-to-twenty-tube module, since it is most difficult to test the permeate from individual tubes or a group of tubes within the module, without interrupting the entire operation of the reverse-osmosis process.
Test probes have been disclosed for use in reverse-osmosis or ultrafiltration modules having straight, permeate flow passageways, through the employment of a test probe, to check individual membrane plate elements, such as, for example, set forth in U.S. Pat. No. 4,228,014, issued Oct. 14, 1980. However, present-day test methods are not wholly satisfactory and fail to permit the collecting and testing of individual test permeate from individual membranes, while permitting the high-pressure flow of the downstream and upstream premeate from the test module. Therefore, the present invention is directed to a probe suitable for use in ultrafiltration or reverse-osmosis membrane modules, particularly a multiple-tube or multiple-plate reverse-osmosis membrane module or group of modules, to permit the simple, rapid and easy collecting and testing of permeate from individual tubes or plates, without disruption of the ultrafiltration or reverse-osmosis process and without the disadvantages of prior-art techniques and test probes.